In recent years, electronic technologies advance rapidly, and the performance of computers and peripheral products becomes increasingly higher, so that various different softwares are introduced to the market constantly and their price becomes much lower than before. Therefore, computers and peripherals are used extensively in our daily life and at work. With this trend, many video product manufacturers spare no effort to develop novel digital electronic devices for the newly developed computer consumer group. For instance, major manufacturers of image-capturing electronic devices (such as digital cameras) bundle various image processing softwares into the digital cameras to attract consumers and gain more marketing niches, and users can use the softwares to read digital images captured by the image-capturing electronic device. Users can connect the image-capturing electronic device with a display device such as a computer or television for viewing the captured digital images on the computer or television or editing the digital images. Such arrangement not only saves the expenses of developing the photos, but also allows users to make various changes and processes to the digital images to greatly reduce the waste of resources including the photo storage space and the related processing.
In general, a portrait photo is the most popular photo among various digital images shot by users and captured by a traditional image-capturing electronic device. When the portrait photo is taken, users generally adjust a diaphragm, a shutter and a position to capture the most appropriate instantaneous scene, and the captured portrait photo will show the best appearance of a photographed person as much as possible. What is the best appearance recognized and accepted by most users? The answer should be that the face of a photographed person shows a natural flawless skin color effect. However, no matter how skillful is a photographer, it is difficult to show a bright and beautiful effect if the photographed person has freckles, scars or moles on his/her face.
In view of the aforementioned issue, present existing image processing softwares generally provide a function of editing or processing digital images, so that users can quickly review and edit the photographed or obtained digital images. In general, the traditional image processing software includes functions of examining a pixel of a flaw digital image, processing the pixel, and removing dark spots. When a user clicks a rubber eraser icon in a toolbox provided by the traditional image processing software for repairing the digital images or removing the dark spots, the user erases the flaw pixels of the data of the digital image, and then clicks a paintbrush icon in the toolbox to repair the erased pixel position. The operating procedure not only involves a high level of complexity, but also requires a high level of skill. General users are not competent to handle the operation.
In the traditional photo development industry, there is a photo retouch service which is a very precise and relatively difficult technique that requires experienced professionals for the service. Regardless of enhancing a flaw negative or digital image, experienced professionals in the related areas of photo retouch, photography and chromatology are required for enhancing the details of flaws or removing the flaws from the negative or digital image, such that the retouched portion or the dark spot portion can show a natural color tone that matches the normal background color. For example, if it is necessary to remove blemishes or dark spots from a forehead of a human face in a face image while maintaining the natural skin color, an experienced professional in this field is required. Even editing tools such as Smear, Smudge, Fuzzy and Imitate in image processing softwares cannot show a natural skin color of the forehead after the blemishes and dark spots are removed, or tremendous time and efforts are required to achieve the effect. Therefore, the editing tools provided by all image processing softwares can provide a partial retouch but not a professional retouch or dark spot removal effect after the flaws on a digital image are retouched. As a result, general users dare not to attempt using the editing tools for enhancing the flaws of a digital image.
Thus, it is an important subject for image processing software and image-capturing electronic device developers to develop an image processing technology for quickly detecting a face image of a digital image captured by an image-capturing electronic device and determining whether or not the face image falls within a skin area range to automatically retouch and remove skin blemishes and dark spots in the area range; so as to assure that each face image can maintain a natural bright, beautiful and flawless skin condition, and allow the image processing technology to meet most of the basic user requirements for photography and effectively compensate the insufficiency of the user's photographic and retouch skills.